#include <iostream>

using namespace std;

int sub(int a, int b){
	return a - b;
}
int sum(int a, int b){
	return a + b;
}
int (*func)(int a, int b);

int main(){
	func = sub;
	cout << (*func)(1, 2) << endl;
	func = &sum;
	cout << (*func)(1, 2) << endl;
	return 0;
}